The syndrome of hereditary angioedema is characterized by recurrent, acute, local circumscribed edema of the skin or mucosa. Episodes of hereditary angioedema are often severe and may be associated with significant morbidity. Replacement therapy with C1 inhibitor represents a vast improvement in our ability to treat or prevent acute attacks of angioedema in these patients. This study will allow patients with hereditary angioedema access to C1-inhibitor for prophylaxis and treatment of acute episodes of angioedema and will also be used to obtain more information on the safety and efficacy of this product.